
IN THE 


UNITED STATES. 

kolH»3 : ^ 

T. EGLESTON, Ph.D. 


From the School of Mines Quarterly, Vol. VII, No. 2, 

January, 1886 . 


































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WORKING PLACER DEPOSITS IN THE UNITED 

STATES. 

BY T. EGLESTON, Ph.D. 

Although it is less than forty years since gold was discovered in 
California, it is already very difficult to ascertain what the truth of 
the history is. This is owing to the fact that long before the real 
discovery, gold which was found in Mexico, was credited to Cali¬ 
fornia, because it was brought to the East by vessels which reported 
it as corning from there. It is also owing in part to the fact that 
but little was known of the country, and that travellers who wrote 
about it, in the desire to feed the appetite for the marvellous, 
reported what they imagined rather than what they found, as com¬ 
ing from them. Others, from selfish or mercenary motives, reported 
what they hoped would bring emigration or raise the value of the 
lands they owned, so that little or no credit should be given to 
what was written previous to about the close of the last century. 
There does not seem to be any truth in the statement that Sir 
Francis Drake found gold in California (New Albion) in 1579. 
That found by Captain Jediah S. Smith during his overland journey 
in 1826 was found in the Sierra Nevada Mountains, and not in 
California. One of the first authentic records of finding gold was 
near the Colorado River, in San Diego County, in 1775. But little 
work was, however, done at this place, as the ground was too poor 
to justify any serious exploitation of it.* The true history of the 
subject appears to be that towards the close of the year 1833*}', or the 
beginning of 1834,}. P. L. Leese came to Los Angeles from Taos, 
New Mexico, bringing grain gold which had been washed out of the 


* Report of the State Mineralogist of California, 1884, p. 217. 
f Eng. and Min. Jour., vol. xxxii., p. 170. 

1 


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2 


placers there. About the same time, a Spaniard named Palacios 
came to the same place from Guaymas, in the State of Sonora, 
bringing with him silver bullion in bars and bricks, and gold in 
grains from Sonora. Both lots together amounted to about ten 
thousand dollars in value, and were for the most part taken out of 
the country, being carried by trading ships to Boston. A part of 
it was worked up by the jewelers in Los Angeles, but no tradition or 
belief that any part of California contained gold in workable quan¬ 
tities can be authenticated up to about 1841. In the early part of 
that year, Don Andres Castillero, a Mexican gentleman of scientific 
education, went to Los Angeles and Santa Barbara, and saw what 
he believed to be evidences of the occurrence of gold near the 
rancho of Las Virgines, and brought with him specimens to Santa 
Barbara, which he said indicated placer gold. In the month of 
June, 1841, Francisco Lopez, who had met Castillero in Santa 
Barbara, while riding over the ranch of San Francisquito, about 
thirty-five miles north of Los Angeles, found gold in a field of wild 
onions, which he took back with him when he returned to Santa 
Barbara. The rumor soon spread, and although very few of the 
Californians had any practical knowledge of gold-washing pro¬ 
cesses, there were a number of natives of Sonora, and other parts 
of Mexico and California, especially in the central part of it, who 
had seen placers worked, and during the first two rainy seasons 
following, a few hundred adventurers, from San Diego to San Luis 
Obispo, flocked into that part of the country and were profitably 
engaged in winnowing and washing gold, which was sold at Los 
Angeles every year. During the first year Lopez is said to have 
taken out about $8000. The value of 18 ounces sent in Novem¬ 
ber, 1842, to the U. S. Mint at Philadelphia, was said to be about 
$340. 

It is an undoubted fact that the Jesuit missionaries for many 
years previous to any reported discovery of it, had known that 
there was gold in the country, and placer deposits had even been 
worked in a small way at their station of San Fernando in Los An¬ 
geles County, but it was discouraged by the priests, who, believing 
that the passion for gold was demoralizing to their people, taught 
them that the working for, and the possession of gold, was detri¬ 
mental to their own interests, and contrary to the true principles 
of religion. The simple folk accepted the dictum, and but for the 


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3 


rumors which came to the East so repeatedly, and from such differ¬ 
ent sources that they could not be treated as myths, the gold might 
not have been discovered for many years. 

A carpenter, named James W. Marshall, who had been attracted 
to California, and was working as a millwright putting up a saw-mill 
on what is now known as Sutter’s mill, at Coloma, El Dorado Co., 
on January 19th, 1848,* made the discovery of gold in the sluice of 
the mill which he was building, and subsequently in other places. 
On the morning of this day, Marshall went out to superintend the 
men, and after closing the forebay gate, shutting off the water, 
walked down the tail-race to study the character of the sand and 
gravel which had been removed during the previous night, for he 
had conceived the idea that there were minerals in the hills, and 
he said so to Sutter, who had only laughed at him. As he was 
examining the debris, his eye caught the yellow metal lodged in 
a crevice on a natural riffle in soft granite, some six inches under 
the water. After a close examination, he suspected that this 
substance was gold. Being a shrewd man, who realized the im¬ 
portance of his discovery, he went on with his work as usual, 
showing the nugget to his men, however, and making some con¬ 
jectures about the extent of the gold-fields, watching carefully for 
any further developments, and in the course of a few days had 
collected a number of qunces of the metal. About four days after 
the discovery, he had occasion to go to Sutter’s Fort, now Sacra¬ 
mento ; so taking the grains with him, he examined the rest of the 
country, and again discovered the same metal in a ravine in the 
foot-hills, and at a place known as Mormon Island. Sleeping 
under an oak tree, some ten miles from the fort, he reached there 
the next morning, and soon put an end to all doubt as to the value 
of the discovery that he had made. It has been claimed that the 
gold was shown to Marshall by Peter L. Weimer, one of his men. 
Both men appear to have been together when the nugget was 
found, but Marshall, having a horse, went to tell Sutter of his 
discovery. No one of the three, however, knew that what had 
been found was gold until it had been assayed at San Francisco. 

These discoveries were soon noised abroad, and caused the aban¬ 
donment of the poor placers of the southern part of the country, 


* Min. Resources U. S„ 1872, p. ill. 




4 


and the influx of a host which depopulated whole villages and 
towns, the city of San Francisco amongst them, and caused the 
wildest excitement all over the East. 

Although the discovery was so memorable, and the results of it 
were so important, it is hardly possible to-day to distinguish the 
spot where it was made. It has been proposed many times that a 
monument should be erected at Coloma, on the site of Sutter’s 
mill, but it has never yet been done, and it is not now likely that 
the spot can be distinguished with sufficient certainty to make it 
worth while to attempt to mark it, so that it is not probable that 
any monument will be erected. 

Marshall died in Kelsey, California, on August 12th, 1885, in 
great poverty and distress. His cattle were killed and his claims 
jumped by men who hunted him during the last years of his life 
in the hope of discovering the secret of finding gold, which they 
believed him to possess. His life was made wretched by his dis¬ 
appointment in never finding the fortune he was seeking, and which 
he always supposed to be almost within his grasp, but which he 
never succeeded in obtaining. Some years before his death, the 
Legislature of California appropriated $200 a month as a pension 
for him for two years. At the end of this time the appropriation 
was not renewed, and the man who had been the means of the 
finding of one billion, six hundred million dollars’ worth of treas¬ 
ure in that State, died a wretched pauper. 

PLACER DEPOSITS. 

When gold is found in sand or gravel, the deposits are called 
placers. These are formed by the accumulations of the debris 
washed down by ancient rivers, often forming deposits of con¬ 
siderable depth and variable richness, which have themselves 
sometimes been again torn up and redistributed by more modern 
streams, forming deposits of comparatively recent origin. We 
have thus the ancient and the modern placer. They have, also, 
sometimes been either wholly formed, or, in some cases, only par¬ 
tially, by the precipitation, of the gold dissolved in the waters of 
filtration, by organic matter.* According to the depth at which the 
gold is found, they are called shallow or deep placers. The shal- 


* Trans. Am. Inst. Mining Eng., vol. ix., p. 643. 




5 


low placers are those deposits which extend to the depth of about ten 
feet or less from the surface. It was in these deposits that the gold 
was originally found in California, and as they are usually very 
rich, they are the most eagerly looked for in the early settlement 
of a country. They exist, scattered over a great extent of terri¬ 
tory, and were so rich and so largely worked that in the first five 
years after their discovery, they produced, notwithstanding the 
wasteful and primitive methods which were used to work them, 
$180,000,000. They are not always of the same richness and 
value, nor are they always capable of being worked. Abundance 
of water is the chief requisite to their successful treatment, and 
even then they are often worked on a wrong theory, and only 
while the pay-dirt continues very rich, and by the rudest and most 
wasteful methods, much more being lost than was ever extracted. 
They were often abandoned as worked out before their real rich¬ 
ness was discovered, some of them having been thus worked over 
two or three times in succession. Even now the Chinese make a 
good living by working over these old tails. Up to the time of 
the invention of hydraulic mining, the shallow placers furnished 
nearly the whole of the gold produced in California. They were 
abandoned, because with the primitive means in use at that day, 
they were no longer profitable, but they are by no means ex¬ 
hausted. It is not improbable that it will, in the near future, be 
found profitable to work them over again on a large scale, both 
because the gold was only partially extracted as well as because 
the gold has concentrated in them from precipitation of the minute 
quantities of gold contained in the waters of infiltration. 

It is estimated* that since 1851 the total amount of gold pro¬ 
duced in the world has been $4,500,000,000. Of this sum, Cali¬ 
fornia has produced about $1,125,000,000, and of this amount, 
$1,000,000,000 have been produced by the working of the aurifer¬ 
ous gravels. 

Not unfrequently small particles of the precious metal were 
found in the roots of the grass or of small shrubs torn up by acci¬ 
dent or design. Sometimes the shining particles of gold were seen 
in the streams whose course lay through the ancient deposits or re¬ 
ceived the drainage waters from them. It was not till long after these 


* Prod. Gold and Silver in U. S., 1881, p. 616. 





6 


modes of occurrence of gold had become known that it was dis¬ 
covered that the precious metal might be found deep down in the 
earth on the bedrock of ancient rivers which had been covered 
with detritus to the depth of hundreds of feet. These modes of 
occurrence give rise to many methods of exploitation of gold, the 
principal of which are known as placer and vein mining. The 
placers are divided into shallow and deep placers, and the method 
of mining varies, according to the manner in which the gold 
occurs in each, as follows : 

In Shallow Placers. 

Gravel mining. 

Sluice mining. 

Beach mining. 

River or bar mining. 

Deep Placers. 

TT , .. . . f Surface mining. 

Hydraulic mining, < . . ° 

l Drift mining. 

Vein Mining. 

» . .. f Dry crushing. 

Amalgamation, \ J ^ 

l Wet crushing. 

Concentration and chlorination. 

Gravel Mining. 

While the shallow placers are near the surface, the deep 
placers, as the name implies, have sometimes their richest por¬ 
tions near the bedrock, which is often two to three hundred 
feet below the surface, where the ground is generally quite poor. 
The formation of both these deposits is owing to the same general 
causes. In many cases the shallow placers are formed by the 
destruction of pre-existing veins, and the accumulation of the gold 
from the detritus by the action of the waters. In others they have 
undoubtedly been formed by the infiltration of small quantities of 
gold in solution in water which has percolated* through them 
from the surface, and has been thrown down in the sand by or- 


* Trans. Am. Inst. Min. Eng., vol. ix., p. 644. 





7 


ganic matter, either dissolved in the water or scattered as solid 
particles through the sand. 

The methods by which shallow placers are worked differ from 
each other more by reason of the differences in the occurrence of 
the gold than because of any difference in the principle of the 
methods employed to extract it. The shallow placers are fre¬ 
quently divided into wet and dry diggings, wet being those which 
are found in the bars and beds of streams, dry being those which 
are found in the gulleys and the bottoms of the streams which are 
large in some seasons of the year, and dry up at others, so that 
water can only be had during certain portions of the year. These 
last claims, where the water is transient, are sometimes called “ gulch 
claims.” They are also sometimes called “ dry diggings,” and are 
not unfrequently very rich in gold. All these were worked in the 
early days, but as they have ceased to be very profitable, they are 
now left to the attention of Chinamen. 

In the very early days the pan was almost the only instrument 
used. It still holds its place as a prospecting tool, although it has 
lost its importance as a working instrument. At first, it was any 
household pan that could be made available. Now it is made of 
Russia sheet-iron, but as its shape is such as is convenient for 
household purposes, the same pan is used for one and the other. 
Upon its skilful manipulation the success of the miners depended, 
and they soon learned to use it so that in the rich deposits or even 
in the poorer ones, they handled it with almost artistic skill. The 
work performed by it was small in amount, but so certain in its 
results, that its revelations were regarded as infallible, and districts 
were overrun or abandoned according to the results which it gave. 
In studying the method of its use, the work may be divided into 
periods, which will generally be found to correspond to five dif¬ 
ferent phases or sets of motions : First. The pan is filled with the 
pay-dirt to about two-thirds of its capacity ; it is then, according as 
water is abundant or scarce, placed in the bottom of a shallow 
stream, or set in a hole filled with water. It is usually placed on 
the bottom so that the operator can use both his hands. Occasion¬ 
ally it is held in one hand while the work is done with the other. 
The whole contents are thoroughly stirred with one or both hands. 
Any lumps that may be found are broken and mashed between the 
fingers, so as to mix them all thoroughly with the water. When the 


8 


whole contents of the pan are in the condition of a thin homo¬ 
geneous mud, the first part of the operation is finished. Second . 
The pan is now taken in both hands, a little behind its diameter, 
raised nearly to the level of the surface of the water, but a little 
below it, inclined away from the operator, so that a very slight 
movement disengages all the light matter and causes it to pass over 
the edge of the pan. This is continued until the water which 
passes off is perfectly clear. There will remain in the pan, after all 
the lumps of clay have been broken up, only pebbles, gravel, heavy 
sand, usually black, and gold-dust. The third stage commences 
with raising the pan above the water and picking out all the large 
pieces, examining them before they are thrown away to see that 
they do not contain gold. The pan contains but little water, so that 
it is quite easy to get rid of the large pieces of sterile matter, either 
picking them out or pushing them over the edge. There will be 
now in the pan little else than small-sized pebbles, the black sand, 
and the gold. The fourth stage is to incline the pan a little under 
the water, causing the next smaller-sized pieces to pass in such a 
thin stream over the edge of the pan that every particle is visible, 
so as to be sure that no gold goes over. The fifth stage consists 
in lifting the pan out of the water with a little water in it, and by 
a dexterous movement of the wrist, causing the sand to pass with 
the water across the bottom of the pan, leaving “ the color ” on the 
opposite side. The pan is then inclined to the side where the sand 
is, and this is washed out with small quantities of water taken up 
in the hollow of the hand and poured on it, causing it to pass out, 
leaving the gold behind. The black sand, however, still remains 
with the gold. There are three ways of getting rid of it. The 
first is with a magnet when the sand is magnetic; the second, by 
dexterously blowing away the sand after it has become dry, and 
the third by the use of mercury. The first two are the methods 
most generally used. 

The ordinary miner’s pan has a flat bottom ; the Mexican and 
Brazilian modification of it is a round piece of wood or metal, which 
is conical, and not over three inches deep in the center, and is 
called a batea. It requires skilful manipulation. On the principle 
of this implement some successful prospecting and working tools 
have been made. 

Great use was made in the early days of the horn spoon , which 


9 


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was cut out of a large ox-horn so as to make a sort of spoon about 
a foot long by two to three inches wide. Horns of dark color, or 
those which were black at one end at least, were much sought after 
for this purpose, as the gold is so much more readily seen on a 
dark than on a light surface. 

All of these were rather prospecting tools than mining imple¬ 
ments. They were, and still are, used in all new fields, both as 
prospecting and working tools while the pay-dirt is rich, but when 
it becomes poor, so that the quantity to be treated in a given time 
must be great, they are no longer capable of treating the large 
amount necessary to give a fair return for the labor, so that if water 
was not abundant, the field was abandoned, or if it was, “ ma¬ 
chines ” were substituted for the pan. The first of these used was 
the “ cradle,” or “ rocker/’ as it is often called. This was a box on 
rockers, having a grating on the top 20 inches square, called the 
riddle, on which the gravel was placed. Water was poured on this, 
which carried the pay-dirt through. It fell on an inclined blanket- 
apron, which carried it to the back of the lower part. On the 
lower part are two riffle-bars, about one inch high. The cradle 
is slightly inclined to the front, so that all the dirt and water put in 
at the top ran down the apron to the back, over the bottom, and 
out at the front. The weight of the water used in the cradle is 
from three to four times the weight of the dirt to be treated, so 
that the work must be done near the water. The very fine gold 
is caught on the blanket-apron, the coarser particles behind the 
riffles; the larger stones are easily picked out from the riddle, and 
the small ones are left to help break up the tough dirt. The mo¬ 
tion of the cradle must be constant to dissolve the dirt and keep it 
loose; otherwise it would pack hard and the gold would run over 
it. The amount of water used must be large, or the excess of dirt 
would not be carried off. When the blanket is to be cleaned up 
the riddle is removed and the blanket taken out and washed in a 
pail. All that is caught has to be panned. If the rocker is to be 
worked by one man, the water is collected in a hole made at his 
right hand. With the left he moves the rocker, and with the right 
he pours water over the dirt. If the “ pay ” is near the water it is 
brought in pails or wheelbarrows. If this cannot be done, it is 
“ packed ” on mules or brought in wagons. If worked by two 
men, one brings the water and the other rocks. If the water 
can be brought by a sluice two men can work rapidly. One 


2 


IO 


man can treat one and a half cubic yards in a day; two men 
can do nearly thr£e times as much. When the gold is fine, the 
cradle, though very cheap, is not economical, as most of this gold 
is lost. When it is coarse and the supply of water uncertain, it is 
a very useful machine ; but its output is very small, and the amount 
of labor required to be done with it is very large. At the best it 
can only treat half the amount that can be washed in a tom, with 
the same amount of labor. Its use has been abandoned in this 
country, except by the Chinese. 

The rocker was replaced by the “ tom,” which was really only 
two launders or sluices, and required a supply of water from 
another sluice. The apparatus consists of an upper sluice-box 
about 14 feet long, 20 inches wide at the upper end and 30 inches 
at the lower, with an incline of a little less than one inch to the 
foot. The lower end of the launder is cut off at an angle of 45 °. This 
is closed by a grating of punched sheet-iron, which allows every¬ 
thing but large stones to pass. This ends over a riffle-box, about 
3 feet wide, and 11 to 12 feet long at the same incline, with five or 
more riffles, into which mercury is put. One man throws in the 
dirt, another stirs it, breaks up the lumps of clay and dirt, and re¬ 
moves the large stones. The gold is caught in the riffles, which 
are sometimes supplemented with blankets. It is worked by from 
two to four men. Two men will do five times as much with the 
tom as with the rocker. It is never worth while to use the tom 
except when the gold is in coarse grains and the quantity of pay 
dirt small. It is now only used by the Chinese, who use it to work 
over the “ exhausted ” tails of the abandoned workings of the early 
miners, and are quite satisfied if they only make seventy-five cents, 
or even less, a day. 

Sluice Mining. 

Almost all the shallow placer deposits are now worked by 
sluices. These sluices are tools of great value and simplicity, and 
their invention and use has probably done as much to increase the 
wealth of California as any other one thing. They were for many 
years the most important instruments used in working the placers. 
The sluice was invented in California, although it has been used 
elsewhere under, however, very different conditions. It has been 
brought to its greatest simplicity, as well as its greatest perfection 
in this country. It is made of rough unplaned boards, and is 


of almost any length over 50 feet, and is not less than 8 inches 
wide and 9 inches deep. The width is usually 16 to 18 inches; 
it maybe thousands of feet in length. The boards are an inch and 
a half thick and 12 feet long, just exactly as they come from the 
mill. The sluice is made in sections. Each section is called a box, 
and as the boards are from 12 to 14 feet long, the sluice is said to 
be made up of so many boxes, which indicates the length per¬ 
fectly. The sides of these boxes are from 18 inches to 2 feet high. 
The bottom boards are sawed for this special purpose, and are 4 
inches wider at the lower than at the upper end. The narrow end 
is intended to fit into the wide one of the upper end of the next 
one below. The sides are nailed upon the bottom. No attempt is 
made to make them tight, as the joints become filled with sand or 
swell tight after a little use. The sluices thus made rest upon 
trestles with a descent varying from 8 to 18 inches in a box. This 
descent is called its grade, and if the fall from one end of the box 
to the other be S inches, it is said to have an 8-inch grade. It is 
generally not desirable to have a grade of less than 8 or more than 
20 inches. The boxes are put up on trestles with great ease and 
taken down as easily, and are transported from one claim to another 
after the placer has been worked out. The amount of water to be 
used in a sluice will depend on a great variety of circumstances, 
especially the quality and quantity of pay dirt to be treated in a 
given time. To work successfully there should be plenty of water. 
In general the depth of water on the bottom of the sluice should 
not be less than two inches. 

The grade depends upon the character of the “ pay,” as the dirt 
containing the gold is called, the length of the sluice, and the 
character of the ground, and the quantity of water available. The 
steeper the grade the more rapidly the dirt will be worked, but the 
greater likelihood there will be of loss in gold. Ordinary dirt will 
be entirely broken up within from 200 to 250 feet of the point 
where it is charged, and from here on, the sluice has but one 
function, namely, to catch the gold. The point being determined 
at which a given quality of dirt will be completely broken up, the 
grade beyond that point is usually lowered, but must always be 
sufficient to carry off the excess of material. It is rare that a sluice 
is made long enough to catch more than 50 per cent, of the gold con¬ 
tained in the sand. Tough, clayey material requires a steeper grade 
than any other. To break up this tough clay the flow must be rapid, 


12 


hut in such a case the sluice must be long. The grade must always 
be less in a short sluice than in a long one. This is owing to the fact 
that there is always danger that a rapid current over a short distance 
will carry off the gold, whereas in a longer distance it would prob¬ 
ably be caught. When the amount to be treated is large, the grade 
should be high, the water abundant, as also when the ground con¬ 
tains a considerable quantity of large boulders. It is unusual for the 
sluice to have the same grade throughout. It is generally made 
steep at first, so as to break up any tough material, and less steep 
afterward. Usually, however, the miner makes the grade conform 
to the lay of the ground, whatever that may be, and regulates the 
height of the trestle by the ease with which he can throw the dirt 
into the sluice. There is always danger, when the dirt contains 
any plastic clay, unless the grade is very high, that this will roll 
over and over on the bottom, and take up the gold which has 
already been deposited and carry it out into the tails at the end of 
the sluice. Such balls may sometimes roll a thousand feet with¬ 
out breaking. For this reason special care is taken to make the 
sluice for this kind of work very steep at first to break up the clay, 
and lower afterwards to catch the gold, or, better still, no attempt 
is made to work the clay in the sluice ; but it is first puddled either 
by hand or machine, and not introduced into the sluice until it is 
in the condition of liquid mud. For this reason when clay 
balls are found in the sluice they should at once be removed, 
broken up, and puddled. When there is but little clay hard 
work is all that is necessary to break up the clay in the sluice, 
but when there is much of it it is cheaper to puddle the whole 
than to run the risk of losing large quantities of gold. When 
there is a great deal of gravel or large stone to be removed, 
under currents are used. For this purpose the end box is left 
open, the bottom for the width of the sluice is covered with 
a grating sufficiently coarse to allow all the fine stuff to pass 
through. Under this a short sluice at right angles to the direction 
of the main sluice is placed, which ends over another sluice 
parallel to the main one but at a lower grade. The material 
coming from above, which is fine enough, passes the grating and 
goes on in the other sluice. The stones and coarse stuff fall out 
at the open end by the force of their own velocity. 

The gold is caught in the lower end of the sluice by various 
devices, which consist of the insertion of some kind of false 


13 

bottom. Even though the boards are rough, with their splinters 
turned up stream, they would soon be worn smooth by the mate¬ 
rial passing over them, and the gold be swept away in the current. 
In order to prevent both the mercury and the material from run¬ 
ning out of the box too quickly, narrow strips of board are fixed 
on the bottom. These maybe either transverse or longitudinal, 
or both. These strips are called “ riffles.” Sometimes, where the 
works are to last for a considerable time, the sides of the sluice are 
protected with a “ lining,” so that they will not be too rapidly 
worn. The longitudinal riffles are from 2 to 4 inches thick, 3 to 7 
inches wide and 6 feet long. From two to four are placed on the 
bottom of the box. Each box will, therefore, contain two such 
riffle bars, and whatever the sluice contains, whether two or more, 
is called a set. They are wedged to their places, and held together 
by a certain number of transverse riffles, so that they maybe easily 
removed for a clean-up. It would not do to put them in per¬ 
manently with nails, as they must be often taken out. Immedi¬ 
ately after a clean-up the riffles are adjusted in the boxes. There 
will thus be in each box, with longitudinal riffles, sections which 
will be 6 feet long, and the length and depth between the riffle 
bars. When the sand is fine, transverse riffles are often used alone, 
but when there is a small amount of pasty material to be broken 
up, zig-zag riffles at an angle of 45 0 are sometimes used. These 
riffles reach nearly across the sluice and are nailed to the bottom. 
The water, with the fine metal, passes over them, while the coarse 
gold and the clay go from side to side with considerable velocity. 
Such riffles do not catch the gold, but only help to break up the 
clay. They are placed in the upper part of the sluice, which must 
always be terminated by the ordinary riffles. Occasionally the 
sluice has a wooden pavement, made of blocks cut across the grain 
of the wood and set several inches apart, but so that they can be* 
easily removed. They are not so permanent as a rock pavement, 
and are not much used except in hydraulic mining. 

The coarse gold is easily caught at the head of the sluice, but 
much of the fine gold would be lost if nothing farther was done to 
catch it. For this purpose mercury is put into the head of the 
sluice, being poured through a strainer to divide it into small 
streams or in some other way broken up into small globules. It 
is usually not added until from one to two hours after the com¬ 
mencement of the working. It is caught in the riffles and amal- 


H 


gamates the fine gold. Sometimes the pores of the riffles bars are 
impregnated with mercury by introducing a gas pipe at one end, 
and filling it with mercury to a considerable height. This is very 
troublesome and scarcely pays for the work it occasions, as the 
riffles must be cleaned by scraping the amalgam formed from the 
wood. It gives as much trouble as copper plates, and is much less 
effective. Copper plates are not often used in placer working. 
These are extensively used in battery sluicing. When they are 
used they are amalgamated by cleaning them first with dilute nitric 
acid, which removes the dirt, and then rubbing them with mercuric 
nitrate or with mercury alone, which is rubbed on with a piece of 
cloth. When the former is used the nitric acid brightens the 
plates, and the mercury at once amalgamates with the copper; 
the green slime of basic copper nitrate thus formed must be 
carefully rubbed off. It is much quicker to clean the copper 
with potassium cyanide, but this requires more care, as if too 
strong a solution is used, or the plates are left in it for too long a 
time, they become black and will not amalgamate. When plates 
are used the current must be slow and the water shallow. A swift 
current carries off the fine gold and deep water does not give 
the gold time to settle. When a speck of gold settles on any part 
of the plate others will collect around it. The more gold there 
is on the plate the better it catches the gold, so that when the 
miners can afford it they amalgamate the plates with gold; when 
they cannot afford that, with silver, and where that cannot be done 
with mercury alone. The amalgam is left to accumulate until it is 
from y to of an inch thick, but not thicker, as there is danger 
of its being stolen. It is then in a hard mass, which must be 
separated by force. To do this the plate is heated until it is a 
little hotter than the hand can bear, and the amalgam separated by 
scraping or with a chisel. A copper plate ,-^th of an inch thick, 
after it is once amalgamated, can be made to last from five to ten 
years if treated with care. An amalgamated copper plate is better 
than a bed of mercury of the same size, but it must be kept clean 
by rubbing. This is usually done with an india-rubber tool, not 
unlike the one so widely used for cleaning windows. The time 
between two clean-ups is called a “ run,” which usually lasts from 
six to ten days. The sluice is generally run only in the day, but 
is sometimes worked day and night. Men must be kept on the 
watch to see that the material coming down does not choke the 


i5 


sluice so as to make the water pour over the sides. Whenever a 
dam commences to form they break it up with an iron bar and 
throw out the stones with a fork. 

Sometimes the sluices are rgade double by running a partition 
through the centre of a large one. This is done either when two 
companies are working on the same ground, in order to avoid the 
extra cost of two separate sluices, or when, because of the variable 
supply of water, it is desirable to run double the amount while the 
water lasts. 

Sometimes, in order to prevent unlawful clean-ups at night, the 
sluices are paved with stone. These paved sluices, however, are 
not usual except in hydraulic mining. An active man can pave in 
a day eight hundred square feet of such sluice, made of cobble 
stone six to eight inches in size. They are laid in loose, but after 
the sand has run over them from half to three-quarters of an hour 
they will be packed quite tight. They are difficult to lay and to 
clean up, but are much more permanent than the wooden pave¬ 
ments. A patrol with a shot-gun loaded with bird shot, and a 
plentiful supply of salt and pepper in the charge, is a much better 
protection against theft. No one who has ever heard of the pain 
caused by the reception of such a charge would ever attempt to 
clean up for his neighbor. 

The gold, quicksilver, and amalgam are caught in the spaces 
between the riffles. All the mercury is introduced into the top of 
the box and passes down with the rest of the material. The water 
should be at least two inches deep over the bottom. Boulders and 
stones must not be allowed to remain in the sluices, as they not 
only grind up the mercury and amalgam into flour, but are in 
danger of becoming wedged and obstructing the free flow of the 
water. They are taken out along the sluice whenever they are 
observed by the man whose duty it is to watch for them. 

Sometimes a sluice is made without any boards by making a 
channel in the earth into which a stream is run. This channel 
is either in the pay dirt itself or in barren ground, the uneven 
bottom of which makes catch places for the gold. When a clean¬ 
up is to be made the water is turned off, and what is collected on 
the bottom panned. Only the coarse gold is saved; the fine is 
entirely lost. As it uses more water for the same amount of ground 
treated, it is only used in temporary workings. Such sluices are 
called “ground sluices.” 


i6 


When the rich dirt is below the level of drainage it is washed in 
a pit. There are two ways of doing this, depending for their ap¬ 
plication on the lay of the ground. One is to pump the water 
used in washing out of the pit wittga Chinese pump, and the other 
to make a covered tail race through which the water can flow to a 
lower level, and cover it as the work progresses with the washed 
ground. This generally necessitates the use of a short sluice, or 
even only of a “ tom.” An active man can throw from three to seven 
cubic yards of dirt a day into the sluice, provided he does not have 
to lift it more than four and a half to five feet; at a less height he 
can do a little more. The quantity depends also somewhat on the 
character of the dirt which has to be moved. Sand without clay 
or boulders is most easily washed. Six cubic yards daily per man 
is fair average work. In a ground sluice where there is no lifting, 
but only shoving to be done, the average work per man will be 
about twenty-five cubic yards per day. When the sluice is worn 
out it is burned and the ashes treated for gold. If it has been 
used for some time the amount of gold recovered in this way will 
sometimes be sufficient to purchase a new sluice. 

To make a clean-up the dirt is no longer put in at the head of 
the sluice. When the water runs entirely clear, five or six sets of 
riffles are taken up at the head of the sluice, their contents washed 
down to the riffles below. The sand is washed over, while the 
gold and amalgam lodge at the riffles and are removed. The next 
sets are then removed, and so on ; sometimes twenty or thirty sets 
of riffles are taken out at a time. The work of a clean-up will 
generally take half a day to a day. It should not be made fre¬ 
quently, as it consumes so much time. It is generally done on 
Sunday. The length of the run will depend on the richness and 
character of the dirt. The amalgam collected is strained through 
a cloth and retorted. 

When the dirt is rich and water cannot be had, the process 
of “ winnowing ” is used. For this purpose all the stones are 
picked out and the dirt is made as fine as possible. It is then 
tossed by two men on a hide or a blanket, with the object 
of having the fine particles carried off by the wind. After this 
has concentrated the pay dirt somewhat, it is again tossed on 
a “ batea .” Where the pay is below the surface, small shafts are 
sunk and galleries run short distances in all directions from it. The 
material brought to the surface is “ winnowed.” This is called 


“ coyoting,” from its resemblance to the burrows of the coyote. 
None but the richest pay can bear this kind of work. Winnowing 
machines are now being made for use. The loss is enormous, but 
where they are used what is obtained is all gain, for without this 
method nothing would be had. 

In very many of the deposits, after the loose sand has been 
worked, there remains below it a hard mass which was recognized 
as containing gold, but which could not be extracted. At first 
this was sent to the stamp-mill, but as all of it did not contain gold, 
and all the coarse boulders which were sterile had to be crushed 
so as to pass through the screens, as well as the fine material which 
contained the precious metal, this method was abandoned. Most 
of this hard material, which is called “ cement,” disintegrates when 
it is exposed to the air for a certain length of time, or is broken up 
by the frost. The cementing material is usually iron oxide, or 
clay. It was then proposed to work it by the hydraulic method, 
interposing in the course of the sluices a large number of “ drops” 
and “ grizzlies ” and “ undercurrents,” in order first to break the 
cement by concussion, then to separate the larger sized boulders 
and catch the gold in the finer material. 

When the deposits are very large such a method may be pos¬ 
sible; generally, as it costs too much in time and labor, it will not be 
profitable. Disintegration by exposure and then washing in large 
revolving iron pans seems to be the most profitable method that has 
as yet been used. The pan bottom is perforated, and is so arranged 
that after a certain amount of the cement has been treated and all 
the fines extracted by water and passed into the sluice, a door in 
the bottom of the pan may be opened to let out the material too 
large to pass through the perforations into the sluices, so that it 
may be thrown out into the tails, which collect on the ground 
below. In the pan four arms with plowshare adjustments revolve 
to break up the cement, and make it fine enough to be carried 
through the bottom into the sluices. When the cement has 
been weathered or frozen and thawed, this work can be rapidly 
done. A pan 5 feet in diameter and 2 feet deep can treat from 40 
to 1 20 tons of such cement per day, depending on the hardness of 
the gravel and the power available to move the pan. 


i8 


Beach Mining. 

It has been known from the very earliest times that gold occurred 
in river sands, and it is there that it is chiefly looked for in the early 
exploring expeditions in any country. That it existed to any ex¬ 
tent in the sands of the sea beaches does not appear to have been 
known, or that sea water even contained a very minute portion 
dissolved in it, was not discovered until within a few years. The 
discover}” of gold on the sea beaches of California and Oregon 
seems to have been like most of the other gold discoveries, the 
result of an accident.* A party of miners prospecting in northern 
California in 1850, of whom Eugene de Bertram was one, were 
forced by the jungle of the main-land to follow the line of the beach. 
In passing along the shore at what is now called Gold Bluff, in 
Klamath County, they found it dazzling yellow in the sunlight and 
covered with gold, which the natural action of the waves had sep¬ 
arated from the beach sands, and so concentrated it that it yielded 
nearly fifty per cent, of precious metal. Collecting some of the sand 
they went first to Trinidad, about thirty miles distant, and from there 
to San Francisco, where a company was formed to mine the beach 
and collect the gold. Excited by the richness of the sample, and 
the truthful though somewhat exaggerated story of the miners, an 
expedition to Gold Bluff was formed, and started from San Fran¬ 
cisco in a revenue cutter. In order to keep the secret from the 
people of Trinidad, they anchored off Gold Bluff, and endeavored 
to land on the spot where the gold had been found. The first boat 
contained six persons, but on nearing the shore it was swamped 
and all were drowned but de Bertram, who was rescued by the 
adroitness of a friendly Indian, who happened to be on the shore 
at the time. The rest of the party returned to Trinidad, and went 
on foot to the beach. But there was no gold there, and no trace 
of it could be found. Discouraged and disheartened, most of the 
party went back to San Francisco, but de Bertram, though weary 
and almost hopeless, yet believing that what he had once seen he 
could find again, waited and watched until a favorable wind and 
tide washed the gold up again. The result of this discovery was 
that soon the beaches were explored, and have since that time been 
worked with moderate profit to the owners; not sufficient, how¬ 
ever to cause any very great excitement or the investment of any 


* Min. Com. Report, 1870, p. 87. 







19 


very large amount of capital. As the concentration is done with¬ 
out cost, and the troublesome question of tails does not have to be 
taken into consideration, since the sea takes care of them, it prom¬ 
ised to last into the distant future, and to give a rich return for the 
labor and capital expended. The excitement caused by their first 
discovery soon received a damper, for with the rude and careless 
methods by which they were worked, not more than one-fifth of 
the gold was separated, and the uncertainty of the winds and the 
waves bringing any up for a considerable length of time, for it was 
necessary that the wind should come from a certain direction, to 
cause the light particles of gold to be brought up on the beach, 
soon proved that no great fortunes were to be made here. These 
beaches were apparently soon exhausted and for a number of years 
were abandoned, on the supposition that they were no longer worth 
working. Many persons, supposing that these golden sands came 
entirely from the deep sea, undertook to dredge and to work the 
sands with complicated and expensive machinery, which, however, 
soon proved to be an entire failure. 

These beach-sands occur in the northern counties of California 
and the southern counties of Oregon, extending from Cape Men¬ 
docino to the Straits of Fuca. They are also found in small quan¬ 
tities as far south as San Francisco, and as far north as Puget 
Sound, but in too small quantities to pay for working, the district 
where it pays to work, being confined to the above limits. The 
diggings extend along the coast for three or four hundred miles. 
The bluffs vary from i io to 500 feet in height. They will average 
200 feet. Most of them are vertical, but they are sometimes over¬ 
hanging and have very narrow beaches at their foot. High up on the 
beach, where the action of the waves is very gentle, the sand is found 
in alternating layers of the fine material composing it, with the 
lighter material on the top. When, on a windy day, the light sand 
of the upper surface becomes dry, it is often blown away to such 
an extent as to leave the heavy black sand on the surface. Lower 
down, however, where the surf breaks, the sand is coarse, and in 
heavy weather may be composed almost exclusively of pebbles. 
In California, as in New Zealand and Australia, these gold sands 
sometimes extend considerable distances into the ocean. Oppo¬ 
site Crescent City, ten miles out to sea, gold was found in the 
soundings brought up by the lead, but all attempts to dredge it 
have failed. These sands have doubtless been deposited by some 


20 


ancient river flowing through the gold region of Oregon and Cali¬ 
fornia, which for ages carried in suspension, in its current, immense 
quantities of auriferous gravel, and which gradually filled its bed 
and the surrounding country with its deposits and subsequently 
became elevated to its present position above the surrounding 
country. 

In some cases the whole length of the bluff is gold-bearing, with 
rich and poor streaks, yielding on the average 20 cents to the cubic 
yard, but the rich streaks giving as much as $135 to the ton, of 
gold .957 fine.* The sand contains gold and platinum in small quan¬ 
tities, in minute scales, most of which are flat, mixed with a very large 
percentage of black, magnetic, and ordinary quartz beach-sand. 
The shape of the grains, which can be seen when they are highly 
magnified, is oblong and doubly convex, with edges thicker than the 
middle, a form which would naturally result from the continued 
pounding of the grains. Their thickness is rarely more than 
0.001 of a line. In length they vary from 0.3 to 0.7 line. Much 
of the black sand is composed of grains of nearly uniform size, 
but they are rounded, so that although the gravity of the 
sand is only one-fourth that of gold, the buoyancy of the latter 
counteracts this, and it is possible to separate them. The gold is 
not only buoyed up by the air, but is as easily moved by the water 
as the black sand itself, so that it requires the greatest skill to ob¬ 
tain “ color ” either with the shovel or the pan. 

It was at first supposed that these beaches were confined exclu¬ 
sively to the coast-line, but it has since been discovered that older 
beaches containing the black sand exist as much as thirty miles 
back of the coast-line, and often at considerable elevations, and in 
such a position as to show that their elevation must have been very 
gradual. The black sand containing the gold, is sometimes cov¬ 
ered to a depth of from three to sixty feet with sterile material. 
In Oregon these are called “ back beaches they are worked either 
by stripping or tunneling. 

All the early methods of extracting gold were based on the dif¬ 
ference in specific gravity. The best of them did not save more 
than 20 per cent, of the gold. Plattner’s process was tried, but 
was found to be too expensive to be used on a large scale, but the 
use of it for a short time confirmed the fact that fully 80 per cent. 


* Prod. Gold and Silver in the U. S.: Burchard, 18S4, p. 557. 


2 I 


of all the gold contained in the sands was being lost. When these 
sands contain gold that can be seen by the microscope, most of it 
is quite bright, though it is covered occasionally by a coating which 
prevents the contact of the mercury. In most cases this appears 
to be of an organic nature, and seems to have been produced sub¬ 
sequently to the formation of the bluff. 

The remarkable purity of the gold obtained from the beaches 
has attracted a great deal of attention. This is undoubtedly owing 
to the fact that this gold being in an extremely finely divided state, 
and wet with the salt water for so long a time, has had the silver 
separated from it in the state of chloride, as is also the case with 
the other metals, leaving the gold almost pure. The value of these 
sands is very variable, depending on the situation and the state of the 
natural concentration at any particular time. Values of from $10 
to $30 a ton are quite common, but the sand often has less, and 
sometimes contains many times this amount. 

As the operation of mining is entirely dependent for success on 
the state of the weather, the direction of the wind, and the force of 
the tide, it is always uncertain, but as it requires very little outlay 
for plant, and not a great amount of labor, it is quite attractive ; 
but as the concentration of the gold in sufficient quantities to work 
is dependent on the weather, the best claims are often unworkable 
for months, during which time the miner must wait patiently for 
any change of wind which will throw the sands up on the beach 
where he can reach them. He may not even be rewarded for many 
weeks for his patience in waiting by any days of favorable winds, 
or even by a single tide. The sea-water cannot be used without 
great loss for concentrating by hand, as it is too heavy, so that the 
beach miner must wait for nature to do the concentrating, which, 
when once effected and collected for treatment, may be entirely 
washed away in a very few minutes by a contrary wind or a heavy 
tide. Such uncertainties do not invite the investment of any large 
amount of capital. 

A favorable wind, with the heavy swells at high tide, drives the 
sand upon the beach. The ebbing tide, as it recedes, washes out 
the fine particles of rock, the lighter materials retreating with the 
water, leaving the heavier ones, the iron, the gold, and the plati¬ 
num, high up on the beach. When the tide is out, this sand can 
be scraped up and “packed” inland out of the reach of the waves, 
to be treated there. In the intervals between two tides, or when 




22 


sufficient has accumulated, the sands are washed in a sluice, termi¬ 
nated by a tom, with the ends and sides turned up. The bottom 
is perforated with holes, and underneath is the slightly inclined 
trough with silver-plated amalgamated copper plates. The sand, 
passing through the holes, strikes the plates; the heavy particles 
of gold are caught on the amalgamated plate and by the mercury, 
while the sands and the float-gold run off at the end of the sluice. 
The method is imperfect, all the more so as the iron-sand is more 
difficult to remove from the buoyant particles of the precious metal 
which characterize these sands, and which are very much lighter 
than those found in ordinary placer mining, chiefly on account of 
its state of very fine division. Much of it floats, and can be made 
to sink only by standing for a very long time, or by heating the 
sand, which is entirely impracticable in a large way. The probable 
quantity of gold is very uncertain, for a single storm will often wash 
out all the sand to the depth of 6 or 8 feet, leaving the rocks 
entirely bare. 

It has been supposed by some that this gold is cast up from the 
depths of the sea, but this theory does not seem to be a probable 
one, for the reasons that the attempts to dredge it in deep water 
have not been successful, because all the bluffs which skirt these 
beaches contain gold, and because the black sand which covers 
the gold is also found in a number of places several miles 
inland, at a height very much above the present level of the sea. 
There are indications that the rivers have in former times been 
blocked by landslides, which have sufficed in some instances to 
turn them from their courses into other channels, and that the 
rivers themselves have carried down immense deposits into the sea, 
where the black sand, the gold, and the platinum in the more tran¬ 
quil waters would tend to separate by gravity. There is also 
abundant evidence that the front of all the cliffs is gradually re¬ 
ceding, and as they contain gold in sufficient quantity to be worth 
working, this sufficiently accounts for the presence of gold in these 
beaches. It is also constantly observed that after a very heavy 
storm which undermines the bluff, and causes large quantities of 
fresh material to fall, the sands are not only richer but the gold is 
coarser than before. Companies have several times been formed 
to work the bluffs, where they were rich enough to be worked. 
This would seem to be a very attractive enterprise, since the bank 
could be cheaply blasted and the sand hydraulicked, while the 


< 


< c 
C ( ( 

( 


23 


sea would do all the concentration and would at the same time 
dispose of all the tails. It has found many enthusiastic adhe¬ 
rents, but has, however, never been extensively tried, for the dis¬ 
tance from which fresh water would have to be brought to wash 
the sand, sometimes 40 or 50 miles, makes the process impracti¬ 
cable. In many cases, especially in the interior of the country, the 
gold of the black sand, which is very fine, does not readily amal¬ 
gamate until after it has been heated, which seems to destroy a 
film of organic matter with which it is coated, and which has conse¬ 
quently prevented the contact of the particles of gold with the mer¬ 
cury. It has been proposed to treat these sands with Plattner’s 
process, but this has also been found to be generally impracticable, 
although the attempt to do so revealed the fact of the enormous 
losses that were being made by treating them by any other pro¬ 
cess. 

It was very generally supposed that in the first mining the 
greater portion of the gold contained in the beach-sand was saved 
in the appliances that were used to collect them, and subsequently 
that the beach-sands themselves had become exhausted. But 
careful assays have since proved that by far the larger part of the 
gold was lost in all the earlier workings in the state of an impal¬ 
pable powder, and in such small particles that it is scarcely visible 
with the microscope. How to separate these fine particles of gold 
from the heavy black sand has been a problem which if the sands 
had been richer would undoubtedly have been solved. The ex¬ 
treme lightness of the microscopic particles of gold, and the much 
greater weight and larger size of the grains of sand make it impos¬ 
sible to separate them by water or air, and in some cases the gold 
itself is coated with some substance which prevents the mercury 
attacking it. As there are millions of tons of sand that contain 
from five to ten dollars in gold to the ton, and are sometimes as 
high as $100, the experiments which were made to save it by 
chlorination and other chemical methods, confirmed the losses 
which were being made in the working of the sands, but suggested 
no practicable method of treatment. 

One of the earliest worked and most famous of these localities is 
at Gold Bluffs in North California. The coast-line after leaving 
Klamath River is very broken and rocky. The sands appear at 
Gold Bluffs about four miles south of the river, where for a long 
distance there is almost an unbroken line of cliffs varying from 100 


24 


to 500 feet in height. Some of these bluffs are vertical, and, in 
some cases, overhanging. They are composed of regular hori¬ 
zontal strata of beach-sand, gravel, and boulders. Beneath these 
are the trunks of very large redwood trees, lying horizontally, and 
stumps standing in their natural position, but below the present 
ocean level, showing a change of level both in the land and sea. 
At low water there is a narrow beach, but when the tide is full the 
sea washes the base of the cliffs. The method of working is to 
wait until the surf strikes the beach at an angle.* When the 
direction of the wind is such that the surf breaks perpendicularly 
on the beach, masses of coarse gravel are thrown up, and no black 
sand, but when the waves strike the beach at an angle, the gravel 
is washed into heaps in certain places, and in others black sand, 
more or less rich in gold, is deposited. During heavy weather the 
beaches cannot be worked, as they are usually too narrow, and the 
action of the waves prevents the deposition of the black sand. 
During a severe storm, the whole surface is covered, so that the 
surf strikes the base of the cliff, and when it subsides the shape of 
the beach will usually be entirely changed. Generally, the sand 
containing the gold lies on the top, but sometimes the black sand 
is covered over with a deposit of barren material, which has first 
to be scraped away before the black sands can be collected. 

At Ophir Beach, near Rogue River, Oregon, the beach below 
high water is washed in a small way by the sluicing process, 
when the sand that is thrown up is rich enough to pay. The super¬ 
intendent examines the beaches every day, collecting the sands 
and scraping up the loose gravel; he pans it, and on finding a 
“prospect,” sends for a mule train, each mule carrying two coarse 
hide or canvas bags, which will contain about 125 pounds each; a 
train of 40 mules would, therefore, transport 10,000 pounds, or five 
tons at a single trip. In order to collect the sand the top gravel 
is stripped and the black sand gathered into piles. The canvas 
sacks are taken from the mules and filled, the mules being trained 
to start on a run for the works the moment they are loaded. As 
in some places the sea comes close up to the cliff, the animals are 
trained to turn their heads toward the cliff, bracing their feet firmly, 
allowing the wave to dash over them, and then going on their way 
on a run till the next wave comes. During a single tide, these 


* Mining Com. Rept., 1874, p. 145. 







25 


mules, under favorable conditions, are able to make three trips, 
when the distance to the working place is not too great. At the 
works the sand is piled up and washed in rockers, long toms, or 
sluices, with amalgamated plates. 

At Randolph, in Oregon, at the mouth of Whiskey Run, the 
gold in the sands was always very fine. No nuggets of more than 
four to five cents in value were found, but the sand was very rich. 
Only a small portion of the gold was saved. Much of the ground 
was worked over six or seven times in succession, and was each 
time found to be remunerative. For a very short time a single 
miner could earn a thousand dollars a day,* but the prosperity was 
of short duration. The town has been in ruins for many years. 
The largest amount ever taken out of any of the California beach- 
claims is said to have been $25,000 in one year. The great diffi¬ 
culty in working the beaches has always been the lack of fresh 
water. They have been washed with salt water pumped from the 
sea, but the amount of gold collected in such cases was only a small 
portion of what was lost. 

All the experience of these beach mines goes to show that im¬ 
mediately after a heavy cave or slide on the banks, the beaches are 
rich in coarse gold, but up to the present time it has not seemed 
profitable to do any bank-blasting or to undertake mining on a 
large scale by the hydraulic processes. The gold is washed up by 
the sea only. Many suggestions have been made that the gold 
would be found in the sea beyond the surf-line, and some attempts 
to dredge for it have been made, but unsuccessfully. 

It was proposed at one time to effect the amalgamation of these 
extremely light particles before endeavoring to concentrate them, 
by heating the sand and quicksilver under water up to the boiling 
point, which would cause the mercury to diffuse itself through the 
entire mass, and thus attack the gold that was in a proper condi¬ 
tion to amalgamate. If this sand had been previously calcined, 
the first calcination and the subsequent heating would be sufficient 
in most cases to remove the coating upon the gold. In some cases 
a chemical treatment of the sand was made, and after all this was 
done, the fine particles of amalgam had still to be collected by 
boiling, and unless they were very rich and fuel plenty, it is evident 
that such a method as this, although patented and supposed to be 


* Min. Com. Rept., 1873, p. 207. 
4 




56 


worth a great deal of money, could not be successful. The process* 
consisted in screening the sand and subjecting it for twenty-four 
hours to a solution of caustic potash and salt, for removing any 
coating upon the gold, and destroying the compounds of sulphur 
which would attack the mercury. The material so treated is 
heated in a pan by a jet of steam, and the quicksilver poured in ; 
it was kept constantly in agitation by the steam, and the movement 
kept up from a quarter to half an hour, by which time the gold 
should have become thoroughly amalgamated. The pulp was dis¬ 
charged into a vat to cool. It is desirable that it should not be 
heated too much, as that divides the quicksilver more than is 
necessary to secure the amalgamation. Care must be taken to use 
pure quicksilver in the process. The cooled material was then 
passed over a series of copper rollers grooved spirally and set, the 
one above the other. These are set over a sluice, three feet wide, 
with amalgamated copper plates and grooved copper rolls. The 
rollers are hollow, i foot in length, and 2 inches in diameter. As the 
amalgam accumulates on the rollers, it is either cleaned off or drops 
into the sluice below. Notwithstanding all that was hoped for it, 
the process was not successful. 

It does not seem likely that beach mining will ever be very 
remunerative ; the uncertainties connected with, the value of the 
sands, and the times when the beaches can be worked, for they 
will often be unworkable for months together, either because the 
storms are so high as to denude the beach, or the weather so calm 
that there is not force enough in the waves to throw up the black 
sand on the beach or wash it down from the cliff. It is not prob¬ 
able that it will ever justify the investment of a large capital. That 
it will, however, yield a fair return for a small outlay, is generally 
true. Persons residing in the vicinity of these beaches have often 
made a fair living by working them when they could be worked, 
but no company, whatever its prospect at the commencement, and 
however rich the beach when they began to work it, has ever been 
able to work these sands with profit for any considerable length of 
time. There are places where if fresh water in sufficient quan¬ 
tities could be had, the bluffs might be worked by hydraulic 
methods, but even this would not be justified if the line of ditch 
was to be very long, or if the storage of the water required the con- 


* Min. Com. Kept., 1875, p. 317. 



27 


struction of large dams. The immediate disposal of the tailings 
by the sea looks at first sight very attractive, but it remains to be 
seen whether the accumulation of enormous amounts of debris 
would not stop the encroachments of the sea, and whether in work¬ 
ing such fine gold on an enormous scale, sufficient of it could be 
caught to make the enterprise profitable. 

River and Bar Mining. 

Bars are the deposits that form in streams which bring down 
auriferous gravel, when the stream strikes a hard rock, and is de¬ 
flected to the other side of its course. Parallel to the line of deflec¬ 
tion, at an angle more or less great to the course of the stream, bars 
will form, on and in which the gold lodges. In a modern stream, 
these bars will, sometimes, rise above the surface, and are worked 
in a small way. The ancient rivers, however, formed bars upon a 
much larger scale. Such bars, running across the channels of these 
ancient streams, most of which have disappeared ages ago, can be 
worked with great profit by hydraulic methods. They are found 
where the river still retains its ancient course, but the diminished 
size of the modern stream will frequently make these bars from 40 
to 50 feet above the present high-water level. They are ordinarily 
worked by the hydraulic methods. Where the bars are simply in 
the rivers of the present time they are of local and transient interest 
only, as they are very soon worked out. The gold they contain 
has sometimes been so concentrated by the action of the stream 
that a single panful has been known to yield more than $100. 
They have been pumped and dredged, but they do not generally 
justify any large expenditure, and all workings based on any large 
yield for a period of time have been unsuccessful. Such plans 
were proposed at Oroville on Feather River, California, but the 
failure was as great and disastrous as the expectations were large 
and promising. The Chinese are, however, working these deposits 
and make a fair living out of these abandoned bars or their tails. 

In very many rivers in California and elsewhere which run 
through alluvial deposits containing gold, or which have abraded 
the outcrops of veins containing it, there is a deposit more or less 
large of gold in their beds. In this case, which is very common in 
California, two methods are used. One is to dredge, or pump the 
sand from the river bed or to undermine it, and another is to 


28 


remove the whole of the water from the river by means of a flume 
and “ flutter wheels,” and then to work the ground of the river bed 
and beneath it. Such experiments as these are extremely hazard¬ 
ous, as the least defect in the construction of a flume or a freshet 
may break up the whole of the works, the outlay for which must 
of necessity be very large. They can, therefore, only be undertaken 
during the summer, when the water is low and when there is no 
danger of sudden rises in the river. Flumes commenced before 
the spring rains were over have more than once been carried away 
before they were finished. Usually these river claims, as they are 
called, are kept dry from leaks in the dams and from the water of 
small streams which enter the sides by wheels which work in the 
flumes constructed to carry off the water by the force of the 
current. 

On Feather River,* in Butte County, California, on the “ Cape 
claims,” two wing dams were constructed across the river. All 
the water above the first dam was carried by a large flume to the 
lower one. The water between the two dams was pumped out by 
wheels run by the current in the flume. The gravel on the river 
bed was washed in sluices, and during forty-two days yielded 
$680,000. Only one-third of the ground had then been washed 
out when the flume was destroyed. Such methods can only be 
employed on small streams in the dry season when there is the 
least water to contend with. The stream must be diverted from 
its course or pumped out. Such methods, as shown by the ex¬ 
ample cited above, are full of risk. They seem very attractive 
when the rich pay dirt is brought up from the bottom and the cal¬ 
culation is made of how much gold is contained in the river bed, 
but it is seldom worth while to flume them for a short distance,— 
generally it will not pay to do it for less than three or four hundred 
feet, and often more must be flumed,—and when all the water has 
been pumped out, derricks run by hurdy gurdy wheels or by hand 
power must be erected to remove the large rocks to get at the gold 
beneath them, with no certainty that the whole of the work will 
not be swept away by a sudden rise in the river. 

When such a method is not practicable, the river is explored to 
find the bars and rich placers. When they are located, a shaft is 
sunk to the depth of 40 to 60 feet above high water-level, and a 


* Prod. Gold and Silver in U. S., 1880, p. 328. 










29 


drift run in the rock under the bars. The gravel is taken out from 
above, hoisted to the surface, and washed in sluices. The water 
pumped from the shaft, can, if necessary, be stored for washing. 
Gravel containing only seventy cents a cubic yard is worked in 
this way. 

Where the quantity of water is, or is likely to be, small, in order 
to economize it, it is the custom to dam the stream, and, when the 
water has accumulated sufficiently, to open the gates and allow it 
to rush out against the gravel with great force. This process, 
called “booming,” is sometimes carried on by hand power and 
sometimes automatically. When the process of “booming” is 
carried on automatically, it is effected with the use of the so-called 
“ shot-gun dam.” This is an automatic discharge gate, so con¬ 
structed as to have the gate of the dam lifted at intervals by 
the water itself; to do this the gate is attached to one end of a 
suspended beam, which has a water-tight box with a valve in the 
bottom, attached to the other. When the dam is full a part of the 
water flowing over passes into a launder, arranged for the purpose, 
which conducts the water to the box. This is so adjusted that 
when it is full it lifts the gate by itself sinking. The contents of 
the reservoir is thus instantly released, and flows with great force 
and rapidity to the point where it is to be used. After it has fallen 
a certain distance the valve of the water box comes in contact with 
an upright post, which opens it and lets the water out. The empty 
box rises and closes the gate. This is repeated at regular intervals, 
giving a heavy head of water and a rapid current every few min¬ 
utes. This method has been extensively used both in Colorado 
and California. Before this method was invented the gate was 
always lifted by hand and required the constant attendance and 
care of one man. By the present method the gate requires to be 
looked after only occasionally. The work is entirely automatic, 
the number of times per hour that the gate is lifted being perfectly 
regular and depending only on the supply of the water. 

It has been proposed, and a great many attempts have been 
made, to raise the gold contained in the river gravels from the 
bottom of the streams with powerful pumping engines, capable of 
raising 25,000 cubic meters in the course of twenty-four hours, 
half of the bulk being water. It is claimed that these pumps are 
cheaper and better than any dredging machines. Notwithstanding 
these assertions, however, neither dredging nor pumping has proved 


30 

successful, for the reason that the river can only separate the gold 
in the same way that a sluice does. The idea of most persons not 
familiar with river sands, is that the sand is deposited in regular 
stratified layers, and that the gold is disseminated regularly through 
them. No one who has any experience in sluice mining would 
believe this, for the whole object of the sluice is to provide places 
where the gold maybe caught in mercury, the bottom of the sluice 
being arranged with reference to this. At the bottom of the river 
the sands are always unequally distributed. The bed rock is never 
even, but is always filled with crevices, into which the gold falls by 
gravity and is not accessible to the dredge. ' Where the river flows 
over a soft gravel, and the bed rock is either turned on its edge or 
is soft from decay, it is well known to gravel miners that the gold 
will penetrate the bed rock sometimes for a considerable distance, 
so that it is frequently worth while to take it up for some depth. 
Dredging and pumping machinery must do their work progres¬ 
sively and systematically, starting from a fixed point and proceed¬ 
ing toward some other. It is impossible for the machine to find 
where the gold lies, and even if every spot were known before¬ 
hand, the irregular nature of the deposit, and the fact that the bed 
rock is often the richest part of it, would make it impossible to 
work a spot here and there, so that in pumping or dredging the 
barren material will be more likely to be raised, even supposing 
the gold is actually there, than that which contains it, as the gold 
is hidden away in pockets beneath the ground, which can be 
reached by the dredge. These processes, therefore, have not been 
successful, and it may be stated as a general proposition that 
if the river bed is poor it will not pay to work it by any method, 
and if it is rich the usual process of damming and fluming, which 
has sometimes proved successful, with all its uncertainties, is prob¬ 
ably the best, as it is certainly the cheapest method of working it 
in dry seasons when the flumes are properly constructed. In such 
a case the practiced eye of the miner distinguishes the points where 
the gold is likely to be found and works those points only, leaving 
the barren material behind, but the machine must take poor and 
rich as it comes, and cannot in any case work the bed rock. 

It would be impossible to state any yield for the placer deposits 
as an average. Those which have been published were interesting 
at the time because they were extraordinarily large, while the poor 
yields have not been made known. The few successes have been 


3 T 


heralded all over the world, but the great army of unfortunate ones 
has not been heard from, and scarcely excites any commiseration 
or sympathy. To average the few successes of the fortunate with 
the immense number of failures would bring the gains down 
so very low that few thinking men, if they were to consider the 
proposition by itself, would care to run the risks of placer mining, 
but every one hopes that he will be one of the fortunate ones, and 
hence many make the attempt. It is doubtful whether, over a 
large and moderately rich district averaging successes and failures, 
the yield is as much as ten dollars a day for each man, and this, 
with the great cost of living in the places and times when such 
mining is possible, is scarcely more than a bare living. How 
many men never found enough to keep their hearts up, and died, 
either in the field or the insane asylum, from grief over the loss of 
all they had saved, or from disappointment at never having realized 
their dreams of wealth, we shall never know, but the number must 
have been very large to bring the average down so low. James 
Marshall’s life and death are an excellent illustration of the proverb : 
“ He that hasteth to be rich hath an evil eye, and considereth not 
that poverty shall come upon him.”* 


* Proverbs, xxviii., 22. 



































































